Another successful build

[Ulf (SM0NOR)]

Another successful build of the project. II had some issues with the controller board. But now works great. It delivers over a 100 watts with a tad over 1 watt in drive.

A question, would it be wise to also monitor SWR before the filter board in case of wrong band selection? Or, can the MRF101 take that?

[jcve...@gmail.com]

Hi Ulf,

Transmitting on a band that is higher in frequency that the LPF is made for can certainly damage the MRF-101 under certain circumstances and should be avoided. I looks like you are just using rotary switch to select the band so there is no microprocessor to check the drive frequency and select the correct filter.  If you don't want to add a second directional coupler you might be able to detect an issue by measuring the drive level and the output level. If you reach 0.5W drive and the output power is less than 25W, something is wrong, shut off the amp.

This type of detector could prevent damage from a variety of faults, not just incorrect filter selection but  broken cables, bad filter components, atc.

73,

Jim WA2EUJ

[Ulf (SM0NOR)]

Yes, it is a rotary switch. My next Learning iteration would be micro controllers. Meanwhile, I want to put the amp in a box and into service. Thus I think an extra coupler is the easiest way to go until I have figured out how to control it from either an HL2 (my base station) or an MCHF (my to-go station). Speaking of micro controllers, I recall I saw something on this site regarding this with a beta developing board available?

73:s – Ulf – SM0NOR

[Tom Moll]

Congratulations Ulf - great you got this working!!

Perhaps my old eyes are deceiving me, but it appears in this photo that the LPF board is not actually wired into the RF circuit.

Am I missing something?

I am still building mine - I finally received most of the parts I have been waiting many months for,

so time to bring this project back up the priority list. 

73 Tom N0BS

[Ulf (SM0NOR)]

Thank you Tom. No, your eyes are perfect. The photo is taken when I still had not reconnected the filter board. During the troubleshooting process I disconnected the boards one by one till I found the fault in the controller board.
I also had to wait for a long time for components. I ordered in May and got the last batch in September.
Please let us know how you progress!
73's - Ulf - SM0NOR